3d Reconstruction of Uneven-Aged Natural Forest In Single Tree Scale

The most important variable that are measured in forest inventory activities are DBH and the height of trees. These variables correlated with other variables (volume, etc) so measuring these is difficult. Acquiring correct and high accuracy information about forests with low prices and a user friendly devise is one of the forest inventory goals. Traditional measuring techniques are low accuracy, and time-consuming. Optical dendrometry was developed for solving this problem and filling this gap. Making 3D reconstruction of objects by using a hand-held digital camera via SfM-MVS (Structure from Motion with Multi-View Streophotogrammetry) technique is a relatively new photogrammetric approach that can be used in forest inventory. the aim of this study was the test potential of an uncalibrated hand-held digital camera with SfM-MVS technique in deciduous and uneven-aged forest environment conditions for the estimation of linear tree metric (DBH). Field data measurements were collected at the Faculty of Natural Resource, Tarbiat Modares University, Nur, Mazandaran, Iran. To this end, a Nikon digital SLR camera and AgiSoft PhotoScan software were used to capture the image and extract point cloud data from the study area with about 2400 m2 and a total of 35 trees. The results of the evaluation DBH estimated by SfM-MVS indicated that this technique has very good potential in trees DBH estimation. The linear relationship between DBH derived via traditional and SfM-MVS techniques was strong (R2=98 %). The RMSE% and Bias% of this technique in tree height estimation were 14.84% and -11.27% respectively. The percentage of omission, commission error, and overall accuracy of the SfM-MVS technique in 3D reconstrucion of all trees was 11.42%, 0%, and 88.57%, respectively.